Drive group for the elevator of an elevator scraper



Dec. 16, 1969 1.. G. EFTEFlELD E AL 3,483,639

DRIVE GROUP FOR THE ELEVATOR OF AN ELEVATOR SCRAPER Filed May 3, 1967 4 Sheets-Sheet 1 INVENTQRS LARRY G. EFTEFIELD LAWRENCE J1 MILLER BY 1 9 fiwwdgyuy 234.14,;-

ATTORNEYS Dec. 16, 1969 L. G.EFTEFIELD ET AL 3,483,639

DRIVE GROUP FOR THE ELEVATOR OF AN ELEVATOR SCRAPER Filed May 5, 1967 4 Sheets-Sheet 2 INVENTORS LARRY e. EFTEFIELD E 15 E LAWRENCE J. MILLER ATTORNEYS Dec. 16, 1969 G. EFTEFIELD ET AL 3,483,639

DRIVE GROUP FOR THE ELEVATOR OF AN ELEVATOR SCRAPER Filed May 5, 1967 4 Sheets-Sheet 5 IN NTORS LARR E FIELD LAWR E J. MILLER ATTORNEYS Dec. 16, 1969 L. EFTEFIELD ET AL 3,483,639

DRIVE GROUP FOR THE ELEVATOR OF AN ELEVATOR SCRAPER Filed May 5, 1967 4 Sheets-Sheet 4 l6 g3 em-=2."

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@Efififi 55 L LAWRENCE I MILLER r l I TTORNYS United States Patent US. Cl. 37-8 2 Claims ABSTRACT OF THE DISCLOSURE An improved drive group for an elevator assembly disposed generally vertically in an elevator scraper where the elevator assembly has a side rail at either side and an endless conveyor disposed for rotation about the elevator assembly. A drive sprocket is mounted at the upper end of each side rail in meshing relation with an endless chain of the conveyor. A hydraulic motor is disposed within the elevator assembly between the side rails and substantially below the drive sprockets. A drive shaft is rotatably disposed between the side rails and substantially below the top sprockets with the motor in rotatable driving relation to a central portion thereof. A separate drive linkage connects each end of the drive shaft with one of the drive sprockets, the drive group including suitable reduction gears for a proper speed ratio between the hydraulic motor and the drive sprockets.

BACKGROUND OF THE INVENTION Elevator scrapers commonly include a separate drive means, usually a hydraulic motor, which is disposed at one end of a drive shaft connecting the drive sprockets at the top of the elevator, the hydraulic motor driving the sprockets and causing rotation of an endless conveyor around the elevator. Numerous disadvantages accrue in such an elevator scraper because of the location of the hydraulic motor driving the elevator. For example the hydraulic motor and the hydraulic lines associated with it are vulnerable to damage when the scraper is operating around overhanging trees, next to banks, etc. The torque reaction on the side rails of the elevator is unequal since all of the torque of the drive motor is introduced adjacent one drive sprocket and remote from the other. Particularly in elevator scrapers having high load capacities where the scraper components are necessarily large, the above noted position of the hydraulic motor substantially raises the center of gravity of the elevator, thus increasing the instability of the scraper. Other disadvantages in the prior art drive groups for an elevator scraper are made apparent in the discussion below.

SUMMARY OF THE INVENTION BRIEF DESCRIPTION OF THE DRAWINGS FIG. 1 is a side view in elevation of an elevator scraper including the improved drive group for its elevator assembly;

FIG. 2 is a plan view in section of the elevator assembly including an embodiment of the improved elevator drive group;

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FIG. 3 is a side view of the elevator assembly of FIG. 2; and

FIG. 4 is a plan view in section of an elevator assembly including an alternate embodiment of the improved elevator drive group.

DESCRIPTION OF THE PREFERRED EMBODIMENTS A preferred embodiment of the invention is described with reference to FIG. 1 which illustrates an elevator scraper 11 mounted behind a tractor 12 and having a scraper bowl 13 which is open at its forward end with a cutting blade 14 disposed at the forward open end of the bowl. An elevator assembly 16 is mounted at the forward open end of the scraper bowl to project forwardly and downwardly to have its lower end above the cutting blade. Referring now to FIG. 3 in particular, and also to FIG. 2, the elevator assembly comprises a pair of longitudinal side rails 17, one at either side of the elevator assembly, and a pair of spreader tubes 18 and 19 which are rigidly interconnected between the side rails at the lower ends of the side rails and toward the upper ends of the side rails respectively. An endless conveyor 21 (FIG. 1), which is disposed for rotation about the elevator assembly, comprises a pair of endless chains, one of which is indicated at 22. Each chain is disposed generally parallel to the side rails, and a series of conveyor flights, one of which is indicated at 23 in FIG. 1 are connected transversely across the chains of the conveyor. To maintain the position of the endless conveyor in its travel about the elevator assembly, an idler is rotatably disposed at the lower end of each side rail to mesh with one of the conveyor chains with suitable carrier rollers 26 disposed along the lengths of the side rails.

To provide an improved drive group within the above elevator assembly, drive means 27 are disposed in driving relation with the conveyor and motor means 31 are disposed within the elevator assembly and connected with the drive means by a suitable drive linkage.

In particular, a drive sprocket 27 is individually mounted for rotation inside an upper end of each side rail 17. Each chain 22 of the conveyor meshes with one of the drive sprockets 27 to be driven thereby. A drive shaft 28 is disposed for rotation within the upper spreader tube 18 and has a spur gear 29 intermediate its ends. The motor means 31 is a hydraulic motor disposed within the elevator assembly between the side rails 17 and adjacent the upper spreader tube 18 such that a shaft 32 which extends from and is driven by the hydraulic motor 31 has a spur gear 33 meshing in driving relation with the spur gear 29 of the drive shaft 28. The spur gears 29 and 33 are of different diameters to provide a first reduction step in the drive group and are enclosed within a suitable housing 34. Each end of the drive shaft 28 is connected to one of the drive sprockets 27 by the generally symmetrical gear drive 36 to provide equal torque reaction at both of the drive sprockets. As seen at the left side of FIG. 2, rotation of shaft 28 is transmitted through bevel gears 38 to a shaft 39 and thence through bevel gears 40 to a short shaft 41. The shaft 41 drives the sprocket through a conventional reducing planetary gear train, not shown, but contained in a housing 42. Suitable housings 43 and 44 enclose the bevel gears 38 and 40, respectively. Some reduction in drive is also obtained through the bevel gear assemblies.

Numerous advantages are readily apparent within the drive group described above. The drive motor being disposed within the elevator assembly is not susceptible to damage from overhanging trees, banks and the like. Further, since the drive motor 31, the drive shaft 28 and the gearing associated therewith is disposed substantially below the upper end of the elevator assembly, the center of gravity of the elevator assembly is substantially lowered and the stability of the scraper is accordingly increased. Also, it may be noted that in prior art configurations where a drive shaft was interconnected between the drive sprockets such as are indicated at 27, hard objects such as rocks could be caught between the drive shaft and one of the elevator flights to be thrown forward by the rotating elevator flights toward the tractor and its operator. Thus, it was necessary to provide a shield in front of the elevator to protect the operator and the tractor whereas the present drive group does not include such a drive shaft and thus obviates the need for such a shield.

It was also customary in the prior art to employ a fly wheel and/or slip clutch as additional components within such a drive group to reduce the effect of pressure peaks caused by increased hydraulic pressure against the elevator flights during loading. To overcome the need for such additional components, the drive shaft 28 of the present drive group is selected of a suitable flexibility to have a torsional wind-up effect with torsional energy stored in the shaft under pressure peak conditions. Further, the spur gears 29 and 33, the drive shaft 28 and the other gearing associated therewith provide an inertia mass which tends to resist either rapid acceleration or rapid deceleration of the drive group. The torsional energy storage ability of the flexible drive shaft and the inertial mass of the gearing serve to reduce the effect of pressure surges in the hydraulic system and assist the motor in sustaining drive of the elevator during momentary peak load conditions, thus eliminating or reducing the need for additional components such as flywheels or slip clutches.

Still further, the present invention provides a symmetrical drive train from the hydraulic motor 31 to each drive sprocket 27 thereby maintaining a uniform torque reaction at each drive sprocket and reducing stresses within the elevator assembly.

An alternate embodiment of the present elevator drive group associated with a similar elevator assembly 16 is illustrated in FIG. 4 and comprises a drive sprocket 51 rotatably mounted inside an upper end of each side rail 17' to mesh in driving relation with one of the continuous conveyor chains 22. A top drive shaft 52 is disposed between and connected to the drive sprockets 51 and has a bevel gear 53 at the approximate center of its length. A motor drive group 54 is disposed within the elevator assembly between the side rails upon mounting members 56 extending upwardly from the upper spacer tube 18' and comprises a hydraulic motor 57 having its output connected through a flywheel 58, a slip clutch 59, a planetary gear mechanism (not shown) in a housing 61 and a planetary gear output shaft 62 extending toward the center of the top drive shaft 52. The planetary gear output shaft 62 has a bevel gear 63 meshing in right angle driving relation with the bevel gear 53 of the top drive shaft to transmit driving power from the motor 57 through the top drive shaft 52 to the drive sprockets 51. The bevel gears 53 and 63 are enclosed in a suitable housing 64.

It is to be noted that this alternate embodiment is a simplified elevator drive group which includes some of 4 into both drive sprockets to drive the elevator conveyor. The inertia mass of the flywheel 58 and the slip clutch 59 serve their usual purposes in association with such an elevator drive group of reducing pressure surges in the hydraulic system, assisting the motor in sustaining drive to the elevator during peak load conditions, as well as limiting the amount of drive which may be transmitted from the motor to the drive sprockets. With the use of the top drive shaft 52, the drive shaft of the gear housing 64 is in close proximity to the conveyor flights 23; thus, it may be desirable to provide a shield to prevent rocks and other hard objects from being caught therebetween and being thrown forward by the rotating motion of the conveyor flights.

What is claimed is:

1. A drive group in a scraper elevator assembly having two inclined, spaced apart side rails and a conveyor including two endless chains supported by rollers for longitudinal rotation about the assembly respectively adjacent the side rails, comprising:

drive sprockets separately and respectively mounted for rotation at an upper end of each side rail, each said sprocket meshing with one of the endless conveyor chains, v

a motor disposed within the elevator assembly below said drive sprockets, and

drive linkage providing generally symmetrical drive trains between said motor and said drive sprockets, said drive linkage including a relatively flexible drive shaft extending transversely between the side rails below said sprockets, said motor being connected in driving relation to a central portion of said drive shaft by a rotatable gear mechanism providing an inertia mass to compensate for momentary power surges in the motor and to assist the motor during peak loads experienced by the conveyor, and connecting drive linkages separately connecting the ends of said drive shaft respectively with said drive sprockets.

2. The combination of claim 1 wherein each of said drive sprockets includes a planetary gear mechanism through which driving power is transmited to said drive sprockets, said connecting drive linkages connecting each end of said drive shaft with one of said planetary gear mechanisms and including reduction gearing, said reduction gearing mechanism between said motor and said drive shaft, said connecting linkage reduction gears and said planetary gears providing a suitable speed relation between said motor and said drive sprockets.

References Cited UNITED STATES PATENTS 1,325,857 12/1919 Olson 198l63 2,698,078 12/1954 Harrison 198-203 3,146,539 9/1964 Speno et a] l988 3,210,869 10/1965 Hein 198--203 3,331,149 7/1967 Rapp 378 1,842,193 1/1932 Penote 37-192 ROBERT E. PULFREY, Primary Examiner E. H. EICKHOLT, Assistant Examiner US. Cl. X.R. 

